1. 1 Energy flow in ecosystems GIOVANNI MARIA SCHIAVON

2. 2 What is an ecosystem? System = regularly interacting and interdependent components forming a unified whole Ecosystem = an ecological system; = a community and its physical environment treated together as a functional system

3. 3 OR, MORE SIMPLY an ecosystem is composed of the organisms and physical environment of a specified area. SIZE: micro to MACRO

4. 4 ENERGY FLOW IN ECOSYSTEMS All organisms require energy for growth, maintenance, reproduction, locomotion, etc. Hence, for all organisms there must be: A source of energy A loss of usable energy

5. 5 H. T. Odum: To understand any system you must understand the next larger system. THE OLD GUY IS RIGHT!

6. 6 Types of energy heat energy mechanical energy (+gravitational energy, etc.) chemical energy Molecular Bonds

7. 7 Autotrophs Autotrophs are called primary producers. Photoautotrophs fix energy from the sun and store it in complex organic compounds (= green plants, algae and some bacteria) photoautotrophs simple inorganic compounds complex organic compounds light

8. 8 Heterotrophs Heterotrophs cannot produce their own food directly from sunlight. They require energy previously stored in something else. heterotrophs simple inorganic compounds complex organic compounds (this may include several steps, with several different types of organisms) heat

9. 9 Heterotrophs can be grouped as: consumers decomposers

10. 10 Consumers feed on organisms or particulate organic matter. Decomposers utilize complex compounds in dead protoplasm. Bacteria and fungi are the main groups of decomposers. Bacteria are the main feeders on animal material. Fungi feed primarily on plants, although bacteria also are important in some plant decomposition processes.

11. 11 The Laws of Thermodynamics Energy flow is a one-directional process. sun---> heat FIRST LAW of THERMODYNAMICS: Energy can be converted from one form to another, but cannot be created or destroyed.

12. 12 “Nothing is created, nothing gets destroyed. Everything mutates” A. Einstein (I think)

13. 13 Energy flow This pattern of energy flow among different organisms is the TROPHIC STRUCTURE of an ecosystem. heat Producers Consumers Decomposers heat

14. 14 TROPHIC LEVELS We can further separate the TROPHIC LEVELS, particularly the Consumers: Producers (Plants, algae, cyanobacteria; some chemotrophs)--capture energy, produce complex organic compounds Primary consumers--feed on producers Secondary consumers--feed on primary consumers Tertiary consumers--feed on secondary consumers

15. 15 Some Key Words Producers = plants etc. that capture energy from the sun Herbivores = plant-eaters Carnivores = animal-eaters Omnivores--eat both animals and plants Specialized herbivores: Granivores--seed-eaters Frugivores--fruit-eaters

16. 16 BASICALLY: Together, these groups make up a FOOD CHAIN E.g., grass, rabbit, eagle CarnivoreHerbivoreProducer

17. 17 SomeFood Chains…

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20. 20 GIOVANNI MARIA SCHIAVON <3

21. 21 QUESTIONS: WHAT IS AN ECOSYSTEM? MAKE A FOOD CHAIN OF YOUR CHOICE. NAME SOME DECOMPOSERS.